Studies offer conflicting health tips

February 20, 2006|By Rob Stein, the Washington Post

WASHINGTON -- For women confused by the latest flurry of health advice about low-fat diets, calcium, vitamin D and hormones, there is a good reason: The findings illustrate how unexpected pitfalls during a major scientific study can yield valuable data but few clear answers.

Research frequently moves in unexpected fits, starts and sometimes puzzling increments. In the case of long, complex projects such as the Women's Health Initiative, the 15-year, $725 million federally funded project that produced the latest results, questionable assumptions and design decisions and unexpected developments can conspire to generate perplexing results.

"We scientists are scratching our heads over some of these results," said Tim Byers of the University of Colorado Health Sciences Center in Denver. "So I'm sure the general public is doing so as well. Unfortunately, it's not always easy to wrap things up in a nice bow and say, `This is the answer.' "

Findings announced during the past two weeks have seemed to overturn long-held medical dictums: Low-fat diets do not clearly reduce the risk for heart disease, breast cancer or colon cancer; hormone therapy is not dangerous for the hearts of younger menopausal women and may actually be protective; and calcium and vitamin D supplements do not appear to offer the strong protection against broken bones and colon cancer that had been thought. Yet no one is saying fat does not matter, hormones are necessarily safe and supplements are useless.

"I can see how a lot of women might be confused," said Dr. Jacques Rossouw, who runs the Women's Health Initiative. "People would like very clear results with a very clear health message, and, unfortunately, these results are not very clear."

Seeking to explain the results, Rossouw and others cited a host of factors: Some of the hypotheses used to design the project may have been flawed or became outdated while the project was under way. It turned out to be much harder than anticipated to get participants to take their pills or stick to diets. Americans started eating differently and taking new medications, perhaps weakening the findings. The project may have been too short, or studied women who were too old, or just too healthy.

Because of the weakness of many findings, the results have produced conflicting interpretations. Subtle but important nuances may have been lost when trying to communicate results quickly to the public.

"Women are being flooded with a lot of information from these studies," said Sherry Marts of the Society for Women's Health Research. "The challenge is trying to put this rush of information in context."